--- /dev/null
+// script.h -- handle linker scripts for gold -*- C++ -*-
+
+// Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
+// Written by Ian Lance Taylor <iant@google.com>.
+
+// This file is part of gold.
+
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+// MA 02110-1301, USA.
+
+// We implement a subset of the original GNU ld linker script language
+// for compatibility. The goal is not to implement the entire
+// language. It is merely to implement enough to handle common uses.
+// In particular we need to handle /usr/lib/libc.so on a typical
+// GNU/Linux system, and we want to handle linker scripts used by the
+// Linux kernel build.
+
+#ifndef GOLD_SCRIPT_H
+#define GOLD_SCRIPT_H
+
+#include <cstdio>
+#include <string>
+#include <vector>
+
+#include "script-sections.h"
+
+namespace gold
+{
+
+class General_options;
+class Command_line;
+class Symbol_table;
+class Layout;
+class Mapfile;
+class Input_argument;
+class Input_arguments;
+class Input_objects;
+class Input_group;
+class Input_file;
+class Output_segment;
+class Task_token;
+class Workqueue;
+struct Version_dependency_list;
+struct Version_expression_list;
+struct Version_tree;
+
+// This class represents an expression in a linker script.
+
+class Expression
+{
+ protected:
+ // These should only be created by child classes.
+ Expression()
+ { }
+
+ public:
+ virtual ~Expression()
+ { }
+
+ // Return the value of the expression which is not permitted to
+ // refer to the dot symbol. CHECK_ASSERTIONS is true if we should
+ // check whether assertions are true.
+ uint64_t
+ eval(const Symbol_table*, const Layout*, bool check_assertions);
+
+ // Return the value of an expression which is permitted to refer to
+ // the dot symbol. DOT_VALUE is the absolute value of the dot
+ // symbol. DOT_SECTION is the section in which dot is defined; it
+ // should be NULL if the dot symbol has an absolute value (e.g., is
+ // defined in a SECTIONS clause outside of any output section
+ // definition). This sets *RESULT_SECTION to indicate where the
+ // value is defined. If the value is absolute *RESULT_SECTION will
+ // be NULL. Note that the returned value is still an absolute
+ // value; to get a section relative value the caller must subtract
+ // the section address.
+ uint64_t
+ eval_with_dot(const Symbol_table*, const Layout*, bool check_assertions,
+ uint64_t dot_value, Output_section* dot_section,
+ Output_section** result_section);
+
+ // Return the value of an expression which may or may not be
+ // permitted to refer to the dot symbol, depending on
+ // is_dot_available.
+ uint64_t
+ eval_maybe_dot(const Symbol_table*, const Layout*, bool check_assertions,
+ bool is_dot_available, uint64_t dot_value,
+ Output_section* dot_section,
+ Output_section** result_section);
+
+ // Print the expression to the FILE. This is for debugging.
+ virtual void
+ print(FILE*) const = 0;
+
+ protected:
+ struct Expression_eval_info;
+
+ public:
+ // Compute the value of the expression (implemented by child class).
+ // This is public rather than protected because it is called
+ // directly by children of Expression on other Expression objects.
+ virtual uint64_t
+ value(const Expression_eval_info*) = 0;
+
+ private:
+ // May not be copied.
+ Expression(const Expression&);
+ Expression& operator=(const Expression&);
+};
+
+
+// Version_script_info stores information parsed from the version
+// script, either provided by --version-script or as part of a linker
+// script. A single Version_script_info object per target is owned by
+// Script_options.
+
+class Version_script_info
+{
+ public:
+ ~Version_script_info();
+
+ // Clear everything.
+ void
+ clear();
+
+ // Return whether any version were defined in the version script.
+ bool
+ empty() const
+ { return this->version_trees_.empty(); }
+
+ // If there is a version associated with SYMBOL, return true, and
+ // set *VERSION to the version. Otherwise, return false.
+ bool
+ get_symbol_version(const char* symbol, std::string* version) const
+ { return this->get_symbol_version_helper(symbol, true, version); }
+
+ // Return whether this symbol matches the local: section of some
+ // version.
+ bool
+ symbol_is_local(const char* symbol) const
+ { return this->get_symbol_version_helper(symbol, false, NULL); }
+
+ // Return the names of versions defined in the version script.
+ // Strings are allocated out of the stringpool given in the
+ // constructor.
+ std::vector<std::string>
+ get_versions() const;
+
+ // Return the list of dependencies for this version.
+ std::vector<std::string>
+ get_dependencies(const char* version) const;
+
+ // The following functions should only be used by the bison helper
+ // functions. They allocate new structs whose memory belongs to
+ // Version_script_info. The bison functions copy the information
+ // from the version script into these structs.
+ struct Version_dependency_list*
+ allocate_dependency_list();
+
+ struct Version_expression_list*
+ allocate_expression_list();
+
+ struct Version_tree*
+ allocate_version_tree();
+
+ // Print contents to the FILE. This is for debugging.
+ void
+ print(FILE*) const;
+
+ private:
+ void
+ print_expression_list(FILE* f, const Version_expression_list*) const;
+
+ bool get_symbol_version_helper(const char* symbol,
+ bool check_global,
+ std::string* pversion) const;
+
+ std::vector<struct Version_dependency_list*> dependency_lists_;
+ std::vector<struct Version_expression_list*> expression_lists_;
+ std::vector<struct Version_tree*> version_trees_;
+};
+
+// This class manages assignments to symbols. These can appear in
+// three different locations in scripts: outside of a SECTIONS clause,
+// within a SECTIONS clause, and within an output section definition
+// within a SECTIONS clause. This can also appear on the command line
+// via the --defsym command line option.
+
+class Symbol_assignment
+{
+ public:
+ Symbol_assignment(const char* name, size_t namelen, Expression* val,
+ bool provide, bool hidden)
+ : name_(name, namelen), val_(val), provide_(provide), hidden_(hidden),
+ sym_(NULL)
+ { }
+
+ // Add the symbol to the symbol table.
+ void
+ add_to_table(Symbol_table*);
+
+ // Finalize the symbol value.
+ void
+ finalize(Symbol_table*, const Layout*);
+
+ // Finalize the symbol value when it can refer to the dot symbol.
+ void
+ finalize_with_dot(Symbol_table*, const Layout*, uint64_t dot_value,
+ Output_section* dot_section);
+
+ // Set the symbol value, but only if the value is absolute. This is
+ // used while processing a SECTIONS clause. We assume that dot is
+ // an absolute value here. We do not check assertions.
+ void
+ set_if_absolute(Symbol_table*, const Layout*, bool is_dot_available,
+ uint64_t dot_value);
+
+ // Print the assignment to the FILE. This is for debugging.
+ void
+ print(FILE*) const;
+
+ private:
+ // Shared by finalize and finalize_with_dot.
+ void
+ finalize_maybe_dot(Symbol_table*, const Layout*, bool is_dot_available,
+ uint64_t dot_value, Output_section* dot_section);
+
+ // Sized version of finalize.
+ template<int size>
+ void
+ sized_finalize(Symbol_table*, const Layout*, bool is_dot_available,
+ uint64_t dot_value, Output_section*);
+
+ // Symbol name.
+ std::string name_;
+ // Expression to assign to symbol.
+ Expression* val_;
+ // Whether the assignment should be provided (only set if there is
+ // an undefined reference to the symbol.
+ bool provide_;
+ // Whether the assignment should be hidden.
+ bool hidden_;
+ // The entry in the symbol table.
+ Symbol* sym_;
+};
+
+// This class manages assertions in linker scripts. These can appear
+// in all the places where a Symbol_assignment can appear.
+
+class Script_assertion
+{
+ public:
+ Script_assertion(Expression* check, const char* message,
+ size_t messagelen)
+ : check_(check), message_(message, messagelen)
+ { }
+
+ // Check the assertion.
+ void
+ check(const Symbol_table*, const Layout*);
+
+ // Print the assertion to the FILE. This is for debugging.
+ void
+ print(FILE*) const;
+
+ private:
+ // The expression to check.
+ Expression* check_;
+ // The message to issue if the expression fails.
+ std::string message_;
+};
+
+// We can read a linker script in two different contexts: when
+// initially parsing the command line, and when we find an input file
+// which is actually a linker script. Also some of the data which can
+// be set by a linker script can also be set via command line options
+// like -e and --defsym. This means that we have a type of data which
+// can be set both during command line option parsing and while
+// reading input files. We store that data in an instance of this
+// object. We will keep pointers to that instance in both the
+// Command_line and Layout objects.
+
+class Script_options
+{
+ public:
+ Script_options();
+
+ // Add a symbol to be defined.
+ void
+ add_symbol_assignment(const char* name, size_t length, Expression* value,
+ bool provide, bool hidden);
+
+ // Add an assertion.
+ void
+ add_assertion(Expression* check, const char* message, size_t messagelen);
+
+ // Define a symbol from the command line.
+ bool
+ define_symbol(const char* definition);
+
+ // Create sections required by any linker scripts.
+ void
+ create_script_sections(Layout*);
+
+ // Add all symbol definitions to the symbol table.
+ void
+ add_symbols_to_table(Symbol_table*);
+
+ // Finalize the symbol values. Also check assertions.
+ void
+ finalize_symbols(Symbol_table*, const Layout*);
+
+ // Version information parsed from a version script. Everything
+ // else has a pointer to this object.
+ Version_script_info*
+ version_script_info()
+ { return &this->version_script_info_; }
+
+ const Version_script_info*
+ version_script_info() const
+ { return &this->version_script_info_; }
+
+ // A SECTIONS clause parsed from a linker script. Everything else
+ // has a pointer to this object.
+ Script_sections*
+ script_sections()
+ { return &this->script_sections_; }
+
+ const Script_sections*
+ script_sections() const
+ { return &this->script_sections_; }
+
+ // Whether we saw a SECTIONS clause.
+ bool
+ saw_sections_clause() const
+ { return this->script_sections_.saw_sections_clause(); }
+
+ // Whether we saw a PHDRS clause.
+ bool
+ saw_phdrs_clause() const
+ { return this->script_sections_.saw_phdrs_clause(); }
+
+ // Set section addresses using a SECTIONS clause. Return the
+ // segment which should hold the file header and segment headers;
+ // this may return NULL, in which case the headers are not in a
+ // loadable segment.
+ Output_segment*
+ set_section_addresses(Symbol_table*, Layout*);
+
+ // Print the script to the FILE. This is for debugging.
+ void
+ print(FILE*) const;
+
+ private:
+ // We keep a list of symbol assignments which occur outside of a
+ // SECTIONS clause.
+ typedef std::vector<Symbol_assignment*> Symbol_assignments;
+
+ // We keep a list of all assertions whcih occur outside of a
+ // SECTIONS clause.
+ typedef std::vector<Script_assertion*> Assertions;
+
+ // The entry address. This will be empty if not set.
+ std::string entry_;
+ // Symbols to set.
+ Symbol_assignments symbol_assignments_;
+ // Assertions to check.
+ Assertions assertions_;
+ // Version information parsed from a version script.
+ Version_script_info version_script_info_;
+ // Information from any SECTIONS clauses.
+ Script_sections script_sections_;
+};
+
+// Information about a script input that will persist during the whole linker
+// run. Needed only during an incremental build to retrieve the input files
+// added by this script.
+
+class Script_info
+{
+ public:
+ Script_info(Input_arguments* inputs)
+ : inputs_(inputs)
+ { }
+
+ // Returns the input files included because of this script.
+ Input_arguments*
+ inputs()
+ { return this->inputs_; }
+
+ private:
+ Input_arguments* inputs_;
+};
+
+// FILE was found as an argument on the command line, but was not
+// recognized as an ELF file. Try to read it as a script. Return
+// true if the file was handled. This has to handle /usr/lib/libc.so
+// on a GNU/Linux system. *USED_NEXT_BLOCKER is set to indicate
+// whether the function took over NEXT_BLOCKER.
+
+bool
+read_input_script(Workqueue*, Symbol_table*, Layout*, Dirsearch*, int,
+ Input_objects*, Mapfile*, Input_group*,
+ const Input_argument*, Input_file*,
+ Task_token* next_blocker, bool* used_next_blocker);
+
+// FILE was found as an argument to --script (-T).
+// Read it as a script, and execute its contents immediately.
+
+bool
+read_commandline_script(const char* filename, Command_line* cmdline);
+
+// FILE was found as an argument to --version-script. Read it as a
+// version script, and store its contents in
+// cmdline->script_options()->version_script_info().
+
+bool
+read_version_script(const char* filename, Command_line* cmdline);
+
+// FILENAME was found as an argument to --dynamic-list. Read it as a
+// version script (actually, a versym_node from a version script), and
+// store its contents in DYNAMIC_LIST.
+
+bool
+read_dynamic_list(const char* filename, Command_line* cmdline,
+ Script_options* dynamic_list);
+
+} // End namespace gold.
+
+#endif // !defined(GOLD_SCRIPT_H)
projects / msp430-binutils.git / blobdiff